Formula Optimization Of Osthole Gel And Its Effects On The IMQ-Induced Psoriasis-like Phenotype

Osthole is a natural occurring coumadin,which was isolated and purified from the seeds of Cnidium monnieri(L.)Cusson.Modern pharmacological studies have shown that osthole possesses a range of pharmacological and biochemical functions,including hepatoprotection,neuroprotection,anti-cancer,anti-osteoporosis,anti-hypertension,antiarrhythmia,anti-aging,and anti-inflammatory properties.The existing research results show that osthole have certain effects to treat or prevent skin disorders.Osthole complex chemical composition,stable under normal storage conditions,no decomposition phenomena pH 5-9 solution.Due to low solubility,poor absorption,rapid metabolism,low bioavailability,osthole formulations often from external use include injection,inclusion complex,microemulsion,solid dispersion,nanoparticles,ointment,gel,patch,etc.Psoriasis is a chronic immune-mediated hyperproliferative inflammatory skin disease in which epidermal hyperproliferation,abnormal differentiation of keratinocytes with lesions at the vascular proliferation and infiltration of immune cells is characterized by the emergence of pathology parakeratosis and inflammatory infiltration,clinical manifestations a clear delineation of erythema and scaling.The pathogenesis of psoriasis is not fully understood,so far,we have not identified a distinct immunogen.In psoriasis,the cutaneous and systemic overexpression of various proinflammatory cytokines,such as interleukins(ILs),tumor necrosis factor(TNF),and interferon-?(IFN-?),has been identified.Complex cellular interactions among epidermal keratinocytes,mononuclear leukocytes,neutrophils,dendritic cells,and activated T cells,together with growth factors,chemokines,and cytokines,are involved in the development of psoriasis.The presence of cytokines,dendritic cells,and T lymphocytes in psoriatic lesions has prompted the development of biologic therapies.Recently,imiquimod(IQM)-induced psoriasis-like inflammation in mice has been reported.IMQ is a ligand for toll-like receptor 7(TLR7)and TLR8,and is a potent immune activator.IMQ's immunomodulatory effects in triggering psoriasis are attributed to stimulation of TLR7 on pDCs and an upregulated type I interferon pathway.IMQ can also interfere with adenosine receptor signaling and augment inflammation.IMQ-induced skin inflammation in mice was immunologically mediated via the IL-23/IL-17 axis,and showed psoriasis-like histopathologic changes(acanthosis,parakeratosis and neoangiogenesis).Transdermal delivery system has become a hotspot for drug delivery systems research.Comparing with oral administration,transdermal administration can ensure high concentrations of the drug concentrated in skin lesions,to avoid hepatic first-pass effect and significant fluctuations of plasma concentrations caused by oral administration,thereby reducing systemic side effects,the frequency of administration and individual differences,improve medication compliance,security for low bioavailability and narrow therapeutic window for drugs.In vitro percutaneous penetration experiment using human skin or animal skin,with the diffusion cell to evaluate the release rate of the drug and the skin penetration characteristics,the materials used for the vitro skin or artificial membrane.In vitro percutaneous test method is simple,easy to implement idealized experimental conditions control.The contents of this research include two parts.The first part: Preparation of osthole gel and its transdermal performance in vitroFirst we determine the osthole gel preparation methods,and then through the orthogonal design the best weigh ratio was determined,and optimize the preparation technology of osthole gel.This study chose the 6 to 8 week old male nude mice as experimental subjects and used the cumulative penetration amount of 12 hours as index to investigate in vitro transdermal performance of osthole gel in Franz vertical diffusion.Results of this section show that the best preparation technology are as follows: Osthole: Carbomer: Azone: EtOH(0.5:0.15:0.5:0.5,w/w/w),added the appropriate amount of distilled water dubbed 10 g gel formulation.The linear equation of 12 h percutaneous permeability in in vitro for optimized osthole gel was y=1.24x+0.37(r=0.9986),and the permeation rate was 1.24?g/cm2/h,12 h average cumulative permeation amount was 14.94±0.51?g/cm2.Methodology of study: To establish HPLC analysis,osthole in 0.1-3.2?g/ml range a good linear relationship,the standard curve was y=99337x+3531.2(r=0.9999).This method chromatographic retention time was 6.4min,day precision,inter-day precision,recoveries are in line with the methodology of the requirements.Samples with 12 h at room temperature stable,RSD is less than 2%.The second part: Preliminary intervene in osthole on imiquimod-induced psoriatic mouse modelFirst effect of osthole on ear thickening and inflammatory response of imiquimod induced mouse model was investigated.According to international PASI scale we evaluate area and severity of inflammation.Combined with biopsy staining,we can inspect ear tissue hyperplasia of epidermis and inflammatory response more visually.Results indicate that the imiquimod induced mouse model exhibit different degree of swelling,thickening,scales,which have some similarity with psoriasis disease lesion.Osthole can relieve the symptoms of psoriatic lesion,reduce PASI score;changes morphological performance to be normal,inhibit epidermis proliferation,reduce parakeratosis of epidermal cells and inflammatory cell.